The stability of ecological communities is critical for the stable provisioning of ecosystem services, such as food and forage production, carbon sequestration, and soil fertility. Greater biodiversity is expected to enhance stability across years by decreasing synchrony among species, but the drivers of stability in nature remain poorly resolved. Our analysis of time series from 79 datasets across the world showed that stability was associated more strongly with the degree of synchrony among dominant species than with species richness. The relatively weak influence of species richness is consistent with theory predicting that the effect of richness on stability weakens when synchrony is higher than expected under random fluctuations, which was the case in most communities. Land management, nutrient addition, and climate change treatments had relatively weak and varying effects on stability, modifying how species richness, synchrony, and stability interact. Our results demonstrate the prevalence of biotic drivers on ecosystem stability, with the potential for environmental drivers to alter the intricate relationship among richness, synchrony, and stability.

生态社区的稳定对于稳定提供生态系统服务至关重要，例如粮食和草料生产，固碳和土壤肥力。预计更大的生物多样性将通过减少物种之间的同步来增强多年来的稳定性，但自然界稳定的驱动力仍然难以解决。我们对来自全球79个数据集的时间序列进行的分析表明，稳定性与优势物种之间的同步程度比与物种丰富度之间的联系更为紧密。物种丰富度相对较弱的影响与理论相一致，即在随机波动下，同步性高于预期时，丰富度对稳定性的影响会减弱，这在大多数群落中都是如此。土地管理，养分添加，气候变化处理对稳定性的影响相对较弱且变化不定，从而改变了物种丰富度，同步性和稳定性之间的相互作用。我们的结果证明了生物驱动因素对生态系统稳定性的普遍性，环境驱动因素有可能改变丰富度，同步性和稳定性之间的复杂关系。